OSOE-415: Orchard-Base-Theme shouldn't lock on every page load

Lombiq.BaseTheme/Manifest.cs

@@ -5,5 +5,7 @@
     Author = "Lombiq Technologies",
     Version = "0.0.1",
     Website = "https://github.com/Lombiq/Orchard-Base-Theme",
-    Description = "The base frontend theme for shared content that are not specific to a specific project's theme."
+    Description = "The base frontend theme for shared code that is not specific to a specific project's theme." +
+      "Warning: themes using this as the base remove the stock Bootstrap resource. If you switch to a different " +
+      "theme, please reload the tenant from Configuration → Tenants in the admin menu."
 )]

Lombiq.BaseTheme/Middlewares/RemoveBootstrapMiddleware.cs

@@ -0,0 +1,76 @@
+using Lombiq.BaseTheme.Constants;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Options;
+using OrchardCore.DisplayManagement.Manifest;
+using OrchardCore.Environment.Extensions;
+using OrchardCore.ResourceManagement;
+using OrchardCore.Themes.Services;
+using OrchardCore.Workflows.Helpers;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Lombiq.BaseTheme.Middlewares;
+
+/// <summary>
+/// Removes the built-in Bootstrap resource if the currently selected theme uses Lombiq.BaseTheme as its base theme.
+/// Themes derived from Lombiq.BaseTheme use Bootstrap from NPM as it's compiled into their site stylesheet. So this
+/// duplicate resource is not needed and can cause problems if not removed. This situation can arise when a module
+/// (such as Lombiq.DataTables) depends on Bootstrap and doesn't explicitly depend on Lombiq.BaseTheme so the built-in
+/// resource would be injected if this middleware didn't remove it.
+/// </summary>
+public class RemoveBootstrapMiddleware
+{
+    private static readonly object _lock = new();
+    private static readonly string[] _resourceTypes = { "stylesheet", "script" };
+
+    private readonly RequestDelegate _next;
+
+    public RemoveBootstrapMiddleware(RequestDelegate next) => _next = next;
+
+    public async Task InvokeAsync(
+        HttpContext context,
+        IOptions<ResourceManagementOptions> resourceManagementOptions,
+        ISiteThemeService siteThemeService)
+    {
+        if (IsCurrentTheme(await siteThemeService.GetSiteThemeAsync()))
+        {
+            var resourcesToClear = resourceManagementOptions
+                .Value
+                .ResourceManifests
+                .Where(manifest => !manifest.GetResources("$" + nameof(FeatureIds.Area)).ContainsKey(FeatureIds.Area))
+                .SelectMany(manifest => _resourceTypes
+                    .SelectWhere(manifest.GetResources)
+                    .SelectWhere(
+                        resources => resources.GetMaybe("bootstrap"),
+                        resource => resource?.Any(IsVersion5) == true))
+                .ToList();
+
+            // This only happens once per tenant process instance, so locking is rare.
+            if (resourcesToClear.Any()) ClearResources(resourcesToClear);
+        }
+
+        await _next(context);
+    }
+
+    private static bool IsCurrentTheme(IExtensionInfo currentSiteTheme) =>
+        currentSiteTheme?.Id == FeatureIds.BaseTheme ||
+        (currentSiteTheme?.Manifest.ModuleInfo as ThemeAttribute)?.BaseTheme == FeatureIds.BaseTheme;
+
+    private static bool IsVersion5(ResourceDefinition definition) =>
+        Version.TryParse(definition.Version, out var version) &&
+        version.Major == 5;
+
+    private static void ClearResources(IEnumerable<IList<ResourceDefinition>> resourcesToClear)
+    {
+        lock (_lock)
+        {
+            foreach (var resource in resourcesToClear)
+            {
+                var toRemove = resource.Where(IsVersion5).ToList();
+                resource.RemoveRange(toRemove);
+            }
+        }
+    }
+}

Lombiq.BaseTheme/ResourceManagementOptionsConfiguration.cs

@@ -27,7 +27,8 @@ static ResourceManagementOptionsConfiguration()
 
         _manifest
             .DefineScript("bootstrap")
-            .SetUrl(Vendors + "bootstrap/js/bootstrap.min.js", Vendors + "bootstrap/js/bootstrap.js");
+            .SetUrl(Vendors + "bootstrap/js/bootstrap.min.js", Vendors + "bootstrap/js/bootstrap.js")
+            .SetVersion("5.1.3");
     }
 
     public void Configure(ResourceManagementOptions options) => options.ResourceManifests.Add(_manifest);

Lombiq.BaseTheme/Startup.cs

@@ -1,13 +1,17 @@
+using Lombiq.BaseTheme.Middlewares;
 using Lombiq.BaseTheme.Migrations;
 using Lombiq.BaseTheme.Services;
 using Lombiq.DataTables.Navigation;
 using Lombiq.HelpfulLibraries.OrchardCore.ResourceManagement;
+using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Routing;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
 using OrchardCore.Data.Migration;
 using OrchardCore.Modules;
 using OrchardCore.ResourceManagement;
+using System;
 
 namespace Lombiq.BaseTheme;
 
@@ -23,4 +27,7 @@ public override void ConfigureServices(IServiceCollection services)
 
         services.AddScoped<IResourceFilterProvider, ResourceFilters>();
     }
+
+    public override void Configure(IApplicationBuilder app, IEndpointRouteBuilder routes, IServiceProvider serviceProvider) =>
+        app.UseMiddleware<RemoveBootstrapMiddleware>();
 }

Lombiq.BaseTheme/Views/Layout.cshtml

@@ -1,17 +1,9 @@
 <!DOCTYPE html>
-@using Microsoft.Extensions.Options
-@using OrchardCore.ResourceManagement
 
 @inject ICssClassHolder CssClassHolder
-@inject IOptions<ResourceManagementOptions> ResourceManagementOptions
 
 <html lang="@Orchard.CultureName()">
 <head>
-    @{
-        // Remove all external Bootstrap 5 resources. (This way we can update Bootstrap independent of OC.)
-        ResourceManagementOptions.RemoveBootstrap5();
-    }
-
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title><shape type="PageTitle"></shape></title>

Readme.md

@@ -20,7 +20,7 @@ Use this as the base theme of any custom frontend themes you create. For instruc
 
 The theme makes use of the [ICssClassHolder](Services/ICssClassHolder.cs) service which provides a scoped container for adding class names from your own code. Use the provided zone names in the [ZoneNames](Constants/ZoneNames.cs) static class to address it.
 
-You may have noticed, that we mentioned Bootstrap 5.1, even though your version of Orchard Core may be still using Bootstrap 5.0. This theme automatically removes the built-in Bootstrap resource manifests and replaces them with the vendor's JavaScript file pulled from NPM. As the Bootstrap stylesheet is already bundled into the site stylesheet there is no need to include that in the resource manifest.
+You may have noticed, that we mentioned Bootstrap 5.1, even though your version of Orchard Core may be still using Bootstrap 5.0. This theme automatically removes the built-in Bootstrap resource manifests on the current tenant and replaces them with the vendor's JavaScript file pulled from NPM. As the Bootstrap stylesheet is already bundled into the site stylesheet there is no need to include that in the resource manifest. If you want to switch over to a different theme that doesn't use this as its base, please reload your tenant by going to Admin → Configuration → Tenants and clicking on the current tenant's Reload button.
 
 Besides the style and layout, the theme also automatically includes a minimalist helper script that eases transition away from jQuery. You don't really need full jQuery now that Internet Explorer is effectively dead (Internet Explorer 11 is going end of life on June 15, 2022 so you should not support it in any new project at this time). The script gives you the `window.helper` object. You can use `helper.ready(($) => {})` in your scripts, where `$(querySelector, baseElement)` returns a JavaScript `Array` of `Element`s.